Spinal implant system

ABSTRACT

A prosthesis for spinal surgery includes a spacer adapted to be secured into the bone and attached to one of a plurality of configuration plates. The configuration plates are interchangeable and each one is configured to utilize a different combination of bone screws, anchors or both. The prosthesis may further include a retaining mechanism to prevent bone screws and/or anchors from backing out.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of the filing date of U.S.Provisional Patent Application No. 62/478,162 filed Mar. 29, 2017, thedisclosure of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates, in general, to an intervertebral systemallowing a surgeon to choose the method of fixation of a spacer at thetime of surgery.

Back pain can be caused by any one of several problems that affectintervertebral discs of the spine, including, for example, degeneration,bulging, herniation, thinning of a disc, or abnormal movement.Generally, the pain is attributable to friction or pressure thatinevitably occurs when one or both adjacent vertebras exert unevenpressure on the disc.

In response to such problems, a typical remedy is to perform spinalfusion, including for example, interbody, intervertebral, cervical,thoracic, or lumbar fusion surgery (all generically referred to hereinas “IF”), which fuse together the two vertebrae adjacent the defectivedisc to form a single, solid bone. Presently, in an IF procedure, theproblematic disc is removed and a spacer is implanted into the space.The spacer generally engages adjacent vertebral bodies to fuse andimmobilize the site and mitigate patient discomfort.

There are a variety of fixation methods used to retain the spacer in itsposition. For example, screws can be inserted into holes in the spacerto engage the bone to secure the spacer thereto. Frequently, a screwback-out mechanism is used to prevent such screws from coming loose fromthe spacer, causing the spacer to become dislodged or unstable in thebody. Alternatively, or in addition to the use of screws, a spacer mayhave anchors coupled thereto that extend into the bone to fix the spacerin position. Whether screws and/or anchors are used may depend on thesurgeon's preference, the patient's anatomy, and the pathology. Existingsystems dedicate the surgeon to one method of fixation and often one wayto anchor it to the adjacent vertebrae.

There is a need in the art for an implant system that allows moreautonomy to a surgeon to choose the method of fixation during surgery.

BRIEF SUMMARY OF THE INVENTION

A first aspect of the invention is a spacer for intervertebral discrepair including a hole for receiving a screw and a channel forreceiving an anchor.

In accordance with certain embodiments of this first aspect, a perimeterof the hole at a location about a central axis of the hole may be fullyenclosed within the spacer. The central axis of the hole may extendthrough a superior surface and a front surface of the spacer. Thecentral axis of the hole may extend through an inferior surface and afront surface of the spacer. The spacer may further include a secondhole having a perimeter at a location about a central axis of the secondhole that is fully enclosed within the spacer. The central axis of thesecond hole may extend through an inferior surface and a front surfaceof the spacer. The central axis of the second hole may extend through asuperior surface and a front surface of the spacer. The spacer mayfurther include a third hole having a perimeter at a location about acentral axis of the third hole that is fully enclosed within the spacer.The central axis of the third hole may extend through a superior surfaceand a front surface of the spacer.

The channel may be a dovetail slot and may extend along a superiorsurface or an inferior surface of the spacer. The channel may be opentoward the superior or inferior surface along which it extends. Thechannel may extend between and intersect both a leading side and atrailing side of the spacer. The channel may extend along a central axisthat forms a non-perpendicular angle with the leading side of thespacer. A perimeter of the channel about a central axis of the channelmay not be fully enclosed within the spacer at any location about thecentral axis of the channel. The spacer may further include a secondchannel that is a dovetail slot extending along the same one of thesuperior and inferior surfaces. The spacer may further include a secondchannel that is a dovetail slot extending along the other one of thesuperior and inferior surfaces.

A second aspect of the invention is a kit for intervertebral disc repairincluding a spacer for intervertebral disc repair including a hole forreceiving a screw and a channel for receiving an anchor, a first plateconfigured to attach to the spacer, the first plate having a holeextension that aligns with the hole when the first plate is attached tothe spacer, and a second plate configured to attach to the spacer, thesecond plate having a channel extension that aligns with the channelwhen the second plate is attached to the spacer.

In accordance with certain embodiments of this second aspect, any of theaforementioned configurations of the spacer can be included in the kit.The kit may further include an anchor configured to extend into thechannel and the channel extension and into one of the adjacent vertebraewhen the second plate is attached to the spacer. The anchor may includean interconnection portion to slidingly engage the spacer, a fixationportion spaced apart from the interconnection portion to fix the anchorto an adjacent vertebra, and a leg connecting the fixation portion tothe interconnection portion. The kit may further include a screwconfigured to extend through the hole and the hole extension and intoone of the adjacent vertebrae when the first plate is attached to thespacer. The channel of the spacer may include four channels and thechannel of the second plate may include four channels configured toalign with the four channels of the spacer when the second plate isattached to the spacer. The kit may further include a securing plateconfigured to attach to the first plate. The securing plate may includea slot therein. The slot may be configured to align with the hole of thefirst plate when the securing plate is attached to the first plate.

The kit may further include a third plate configured to attach to thespacer, the third plate having a hole extension that aligns with thehole when the third plate is attached to the spacer and a channelextension that aligns with the channel when the third plate is attachedto the spacer. The hole of the spacer may include two holes and thechannel of the spacer may include two channels, and the hole of thirdplate may include two holes and the channel of the third plate mayinclude two channels, the holes and channels of the third plateconfigured to align with the holes and channels of the spacer,respectively, when the third plate is attached to the spacer. The kitmay further include a securing plate configured to attachinterchangeably with the first and third plates. The securing plate mayinclude a slot therein. The slot may be configured to align with thehole of the first plate or the hole of the third plate when the securingplate is attached to the first or third plate.

A third aspect of the invention is a kit for intervertebral disc repairincluding a spacer for intervertebral disc repair including a hole forreceiving a screw and a channel for receiving an anchor, and a securingplate configured to engage the spacer, wherein a portion of the securingplate overlies the hole and the channel when the securing plate isengaged to the spacer to block a screw from backing out of the hole andto block an anchor from backing out of the channel.

In accordance with certain embodiments of this third aspect, any of theaforementioned configurations of the spacer can be included in the kit.The securing plate may further include a slot configured to allow theretaining mechanism to compress. The kit may further include an anchorconfigured to extend into the channel and the channel extension and intoone of the adjacent vertebrae when the second plate is attached to thespacer. The anchor may include an interconnection portion to slidinglyengage the spacer, a fixation portion spaced apart from theinterconnection portion to fix the anchor to an adjacent vertebra, and aleg connecting the fixation portion to the interconnection portion. Thekit may further include a screw configured to extend through the hole ofthe spacer and into one of the adjacent vertebrae.

A fourth aspect of the invention is a method of using of a kit forintervertebral disc repair, the kit including a spacer forintervertebral disc repair including a hole for receiving a screw and achannel for receiving an anchor, a first plate configured to attach tothe spacer, the first plate having a hole extension that aligns with thehole when the first plate is attached to the spacer, and a second plateconfigured to attach to the spacer, the second plate having a channelextension that aligns with the channel when the second plate is attachedto the spacer, with the method including the steps of attaching one ofthe first or second plates to the spacer, inserting the spacer-plateconfiguration into the disc space, and inserting a screw into the holeand the hole extension of the first plate and into communication with anadjacent vertebra or inserting an anchor into the channel and thechannel extension of the second plate and into communication with anadjacent vertebra.

In accordance with certain embodiments of this fourth aspect, any of theaforementioned configurations of the kit can be utilized by the method.The method may further include the step of evaluating bone integrity ofvertebrae adjacent the disc space. The method may further include thestep of selecting the first plate or the second plate to be used withthe spacer. The inserting step may be carried out in an anteriorapproach. The inserting step may be carried out in a lateral approach.

A fifth aspect of the invention is a method of using a kit forintervertebral disc repair, the kit including a spacer forintervertebral disc repair including a hole for receiving a screw and achannel for receiving an anchor, a first plate configured to attach tothe spacer, the first plate having a hole extension that aligns with thehole when the first plate is attached to the spacer, a second plateconfigured to attach to the spacer, the second plate having a channelextension that aligns with the channel when the second plate is attachedto the spacer, and a third plate configured to attach to the spacer, thethird plate having a hole extension that aligns with the hole when thethird plate is attached to the spacer and a channel extension thataligns with the channel when the third plate is attached to the spacer,with the method including the steps of attaching one of the first,second, or third plates to the spacer, inserting the spacer-plateconfiguration into the disc space, and inserting a screw into the holeand the hole extension of the first plate and into communication with anadjacent vertebra, inserting an anchor into the channel and the channelextension of the second plate and into communication with an adjacentvertebra, or inserting a screw into the hole and the hole extension ofthe third plate and into communication with an adjacent vertebra andinserting an anchor into the channel and the channel extension of thethird plate and into communication with an adjacent vertebra.

In accordance with certain embodiments of this fifth aspect, any of theaforementioned configurations of the kit can be utilized by the method.The method may further include the step of evaluating bone integrity ofvertebrae adjacent the disc space. The method may further include thestep of selecting the first plate, the second plate, or the third plateto be used with the spacer.

A sixth aspect of the invention is a method of using a kit forintervertebral disc repair, the kit including a spacer forintervertebral disc repair including a hole for receiving a screw and achannel for receiving an anchor, a first plate configured to attach tothe spacer, the first plate having a hole extension that aligns with thehole when the first plate is attached to the spacer, a second plateconfigured to attach to the spacer, the second plate having a channelextension that aligns with the channel when the second plate is attachedto the spacer, a third plate configured to attach to the spacer, thethird plate having a hole extension that aligns with the hole when thethird plate is attached to the spacer and a channel extension thataligns with the channel when the third plate is attached to the spacer,and a securing plate configured to attach interchangeably with any ofthe first, second, and third plates, with the method including the stepsof attaching one of the first, second, or third plates to the spacer,inserting the spacer-plate configuration into the disc space, insertinga screw into the hole and the hole extension of the first plate and intocommunication with an adjacent vertebra, inserting an anchor into thechannel and the channel extension of the second plate and intocommunication with an adjacent vertebra, or inserting a screw into thehole and the hole extension of the third plate and into communicationwith an adjacent vertebra and inserting an anchor into the channel andthe channel extension of the third plate and into communication with anadjacent vertebra and when the first plate or the third plate isattached to the spacer, attaching the securing plate to the first plateor the third plate. In accordance with certain embodiments of this sixthaspect, any of the aforementioned configurations of the kit can beutilized by the method.

A seventh aspect of the invention is a method of using a kit forintervertebral disc repair, the kit including a spacer forintervertebral disc repair including a hole for receiving a screw and achannel for receiving an anchor, and a securing plate configured toengage the spacer, wherein a portion of the securing plate overlies thehole and the channel when the securing plate is engaged to the spacer toblock a screw from backing out of the hole and to block an anchor frombacking out of the channel, with the method including the steps ofinserting the spacer into disc space, inserting a screw into the hole ofthe spacer, and attaching the securing plate to the spacer. Inaccordance with certain embodiments of this seventh aspect, any of theaforementioned configurations of the kit can be utilized by the method.

An eighth aspect of the invention is a method of using a kit forintervertebral disc repair, the kit including a spacer forintervertebral disc repair including a hole for receiving a screw and achannel for receiving an anchor, and a securing plate configured toengage the spacer, wherein a portion of the securing plate overlies thehole and the channel when the securing plate is engaged to the spacer toblock a screw from backing out of the hole and to block an anchor frombacking out of the channel, with the method including the steps ofinserting the spacer into disc space, inserting an anchor into thechannel of the spacer, and attaching the securing plate to the spacer.In accordance with certain embodiments of this eighth aspect, any of theaforementioned configurations of the kit can be utilized by the method.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the subject matter of the presentinvention(s) and of the various advantages thereof can be realized byreference to the following detailed description in which reference ismade to the accompanying drawings in which:

FIG. 1 is a perspective view of a spacer of a prosthesis, in accordancewith one embodiment of the present invention.

FIG. 2 is an anterior view of the spacer of FIG. 1.

FIG. 2A is a cross section view along section A-A as shown in FIG. 2.

FIG. 3 is a perspective view of a configuration plate which may beattached to spacer 12 of FIG. 1, the configuration plate being inaccordance with one embodiment of the present invention.

FIG. 4 is an anterior view of the configuration plate of FIG. 3.

FIG. 4A is a cross section view along section A-A as shown in FIG. 4.

FIG. 5 is a posterior view of the configuration plate of FIG. 3.

FIG. 6 is a superior view of the configuration plate of FIG. 3.

FIG. 7 is a perspective view of a configuration plate which may beattached to spacer 12 of FIG. 1, the configuration plate being inaccordance with a second embodiment of the present invention.

FIG. 8 is an anterior view of the configuration plate of FIG. 7.

FIG. 8A is a cross section view along section A-A as shown in FIG. 8.

FIG. 9 is a perspective view of a configuration plate which may beattached to spacer 12 of FIG. 1, the configuration plate being inaccordance with a third embodiment of the present invention.

FIG. 10 is an anterior view of the configuration plate of FIG. 9.

FIG. 10A is a cross section view along section A-A as shown in FIG. 10.

FIG. 11 is a superior view of the configuration plate of FIG. 9.

FIG. 12 is a perspective view of a retaining mechanism which may beattached to configuration plates of FIGS. 3 and 7 for use in theprosthesis of one embodiment of the present invention.

FIG. 13 is a perspective view of a prosthesis having a spacer of FIG. 1,the configuration plate of FIG. 3, and the retaining mechanism of FIG.12, in accordance with one embodiment of the present invention.

FIG. 14 is a perspective view of a spacer to be used in a prosthesis, inaccordance with another embodiment of the present invention.

FIG. 15 is an anterior view of the spacer of FIG. 14.

FIG. 16 is a superior view of the spacer in FIG. 14.

FIG. 17 is an anterior view of a retaining mechanism which may beattached to the spacer of FIG. 14.

FIGS. 18A-D are various perspective views of the prosthesis with thespacer of FIG. 14 and including in some instances, bone screws oranchors, and including in some instances, the retaining mechanism ofFIG. 17.

FIGS. 19A-B are perspective views of a prosthesis having a spacer andtwo embodiments of plates connected thereto for use in cervical surgery.

FIGS. 20A-B are perspective views of a prosthesis having a spacer andtwo embodiments of plates connected thereto for use in lateral lumbarsurgery.

FIGS. 21-23 are perspective views of an anchor to be used with thespacers of FIG. 1 and FIG. 14, in accordance with certain embodiments ofthe present invention.

DETAILED DESCRIPTION

In describing certain aspects of the present invention(s), specificterminology will be used for the sake of clarity. However, theinvention(s) is not intended to be limited to any specific terms usedherein, and it is to be understood that each specific term includes alltechnical equivalents, which operate in a similar manner to accomplish asimilar purpose.

Referring to FIGS. 1-2, an implant or spacer 12 according to oneembodiment of the present invention includes top and bottombone-contacting sides 18 and 20, respectively, a leading side 24, atrailing side 22 opposite the leading side 24, and two lateral sides 26extending between the leading and trailing sides 22, 24. In theillustrated embodiment, the spacer 12 has a generally rectangularprismatic shape with posterior-facing edges extending between top andbottom sides 18, 20 being rounded. Alternatively, the spacer 12 may be asquare, oval, circular, elliptical, or any other shape in the superiorview. Top and bottom sides 18 and 20 may be flat, concave, convex, orany other shape in the anterior or lateral views. In particular, in alateral view, the top and bottom sides 18, 20 may be curved or angled togive spacer 12 a lordotic shape.

Spacer 12 includes a hole 31 having at least a portion that is fullyenclosed within the body of spacer 12. That is, hole 31 has a perimeterat at least one location about its central axis that is fully enclosedwithin the body of implant 12. The central axis of hole 31 extendsthrough a superior surface and a front surface of the spacer, such thathole 31 extends at an angle from trailing side 22 to top side 18. Asshown in FIGS. 1 and 2, hole 31 may be positioned generally centrally orbetween lateral sides 26 on trailing side 22 of spacer 12. Spacer 12includes two additional holes 33 each also having a perimeter at atleast one location about its central axis that is fully enclosed withinthe spacer. The central axes of holes 33 extend through an inferiorsurface and the front surface of the spacer, such that the holes 33extend into spacer 12 at an angle from trailing side 22 to bottom side20. Each hole 33 may be positioned between central line 11 and one ofthe lateral sides 26. In other embodiments, spacer 12 may have fewer ormore holes positioned in the same or different locations and extendingthrough spacer 12 at different angles to accommodate screws. In certainembodiments, the holes may only extend toward one of top and bottomsides 18, 20. In yet another embodiment, any or all of the holes mayhave a perimeter that is only partially enclosed within the spacer.

Spacer 12 has channels or tracks 36, 38 that extend across spacer 12between and intersect with both leading side 24 and trailing side 22. Asshown in FIGS. 1 and 2, channels 36, 38 are dovetail slots that areformed in spacer 12 in a truncated I-beam shape. However, in otherexamples, the channels 36, 38 may have a variety of shapes, includingcircular, rectangular, keyhole, T-shaped, etc. Each channel ispreferably configured to have an enlarged profile away from the adjacentsurface so that an anchor disposed therein can be secured from migratingout of that channel toward the surface. Each dovetail slot is configuredto slideably engage with a mating feature on an anchor 80, described indetail below. Spacer 12 includes four channels, two channels 36 that areopen toward top side 18 of spacer 12 and extend across top side 18 andtwo channels 38 that are open toward bottom side 20 of spacer 12 andextend across bottom side 20. As shown in FIGS. 1 and 2, each channel36, 38 may extend along a central axis that is angled, i.e. forms anon-perpendicular angle, with respect to leading side 24 of spacer 12.Channels 36, 38 may extend across top and bottom sides 18, 20 at anangle with respect to leading side 24 so that, for example, two channels36 are nearer each other on trailing side 22 than on leading side 24such that they diverge. Further, each channel 36, 38 may have aperimeter about its central axis that is not fully enclosed withinspacer 12 at any location along its central axis so that it is open inthe superior or inferior direction, as the case may be.

Spacer 12 includes a connection feature to allow for a mating connectionwith a corresponding feature on a cover plate 40, 140, 240. In theillustrated embodiment, the connection feature of spacer 12 is recesses39, which are shaped and sized to couple with the correspondingconnection feature of plates 40, 140, 240 (e.g. clips 55, 155, 255described below). However, in other examples, the connection features ofspacer 12 and the plates may include any feature known in the art toallow the two bodies to connect, such as for example compressiontechnology. Other embodiments may also include recesses 39 and clips 55,155, 255 in different quantities and/or in different locations, such ason lateral surfaces of the implant. As shown in FIGS. 1 and 2, tworecesses 39 are disposed on top side 18 and one recess 39 is disposed onbottom side 20, each of which extend from leading side 24 towardtrailing side 22. Each recess 39 is positioned generally adjacent to ahole 31, 33, though such positioning is not required. In otherembodiments, spacer 12 may include more or fewer recesses 39 which maybe disposed in a variety of positions on top and bottom sides 18 and 20and/or lateral sides 26 to accommodate and secure a cover plate such ascover plate 40. As shown in FIG. 2A, recesses 39 are each shaped toinclude a groove 39 a that extends into spacer 12 from the respectivetop or bottom side 18, 20 to allow for a mating feature of cover plate40 to more securely attach cover plate 40 to spacer 12. In the presentembodiment, both recesses 39 and grooves 39 a are rectangular; however,in other examples, the recesses and grooves may take other shapes,including square, circle, oval, trapezoidal, etc.

Spacer 12 and/or the attached plate may further include teeth orserration on each of top and bottom sides 18, 20 to provide for fixationwith adjacent vertebrae and may include openings to allow for receipt ofbone in-growth material.

A prosthesis 10 according to one embodiment of the present inventionincludes a plate 40, 140, or 240 that attaches to spacer 12. Plates 40,140, and 240 are interchangeable and are each connectable with spacer 12to form a differently-configured prosthesis 10. Each plate 40, 140, 240provides a different variation of fixation features, so that duringsurgery, a surgeon can choose which plate is most appropriate to use fora particular patient and/or objective. Plates 40, 140, 240 can includeone or more of screw holes, dovetail slots, or both, so that bonescrews, anchors, or both may be inserted into prosthesis 10,respectively. After selecting one of the plates, the surgeon can thenattach it to spacer 12.

Plates 40, 140, and 240 share several common features, which aredescribed first. Although reference numerals correspond to configurationplate 40, similar features included in plates 140 and 240 arerepresented with like numerals.

As shown in FIGS. 3-6, plate 40 includes a top side 42, a bottom side 44opposite the top side, opposing lateral sides 46 extending between thetop side 42 and the bottom side 44, a trailing side 48, and a leadingside 50 opposite the trailing side.

Plate 40 includes a connection feature to connect the plate to spacer12. In the illustrated embodiment, the connection feature of plate 40 isclips 55. However, as described above with respect to recesses 39, clips55 may be any corresponding feature that allows for connection of spacer12 and plate 40. Additionally, the connection feature may be one suchthat only one common connection feature is required between spacer 12and plate 40. In the illustrated embodiment, clips 55 each extendposteriorly away from leading side 50. As shown in FIGS. 5 and 6, plate40 includes two clips 55 positioned generally superiorly of holes 43 andone clip 55 positioned generally inferiorly of hole 41. Clips 55 aresized and shaped to fit in recesses 39 on spacer 12. As shown in FIG.4A, each clip 55 includes a protrusion 55 a extending toward center line53 of plate 40, such that clips 55 positioned on the top side 42 of theplate have protrusions 55 a extending inferiorly, and clip 55 on thebottom side 44 has a protrusion 55 a that extends superiorly.Protrusions 55 a are configured to snap into grooves 39 a of spacer 12.Protrusions 55 a are rectangularly shaped, but in other embodimentsclips 55 and protrusions 55 a can have any shape that corresponds to theshape of the recesses 39 and grooves 39 a. That is, the location andnumber of clips 55 can be dependent upon the location and number ofrecesses 39 on spacer, and vice versa. Clips 55 and protrusions 55 a canbe positioned at any location on plate 40 that is free from intrusion ofanother feature, i.e. free space, such as for example, lateral sides 46.Further, clips 55 and protrusions 55 a of plate 40 snap into therecesses 39 and an interference, friction fit causes secure attachmentbetween spacer 12 and plate 40. In some embodiments, the friction fit isachieved by either slightly oversized or slightly undersized protrusions55 a relative to grooves 39 a. Upon attachment of plate 40 to spacer 12,plate 12 is generally flush with spacer 12 so that there is little to nospace between plate 40 and spacer 12.

As illustrated in FIGS. 3-6, plate 40 includes two holes, or holeextensions, 43 extending from trailing side 48 at a downward angle toleading side 50. Holes 43 are configured to correspond to and align withholes 33 of spacer 12, such that a bone screw can extend through holes43 and 33 when plate 40 is attached to spacer 12 and engages the bone.The downward angled approach of holes 43 is shown in FIGS. 3 and 4.Plate 40 further includes hole 41 extending from trailing side 48 at anupward angle to leading side 50. This angled approach of hole 41 isillustrated in FIGS. 3-4. In this manner, plate 40 is configured forinsertion of angled screws, such as bone screws, to secure prosthesis 10to superior and inferior vertebrae. In other examples, holes 41, 43extend through plate 40 at a variety of angles and may have diametersgreater or less than those shown. In the present embodiment, holes 41,43 are not threaded and have an annular shoulder 51 that can abut a headof the screw to limit insertion depth. In other examples holes 31, 33,or alternatively holes 41, 43, may be provided with threads.

Plate 40 further includes a connection feature to connect with retainingmechanism 60, described below. In the illustrated embodiment, theconnection feature is recesses 49 and grooves 49 a that aresubstantially similar to recesses 39 and grooves 39 a of spacer 12. Theshape of the presently shown recesses 49 and grooves 49 a can best beseen in FIG. 4A. Recesses 49 of plate 40 are adapted to mate with acorresponding connection feature on retaining mechanism 60, describedbelow. Like recesses 39 of spacer 12, recesses 49 may be any featureknown in the art that provides for connection of plate 40 with retainingmechanism 60, and the connection feature is not limited to therecess-clip configuration. Plate 40 has one recess 49 positioned on topside 42 generally superior to hole 41 and two recesses 49 positioned onbottom side 44 generally inferior to holes 43. Trailing side 48 alsoincludes a recessed surface 48 a surrounded by a raised surface 48 bthat acts as a rim. Recessed surface 48 a is rectangular in nature withrounded corners and is dimensioned to fit retaining mechanism 60 thereinso that an outer surface of retaining mechanism 60 is flush with raisedsurface 48 b when plate 40 and retaining mechanism 60 are assembledtogether.

Referring to FIGS. 7-8, another embodiment according to the presentinvention is a plate 140 that includes hole 143 that are identical toholes 43 of plate 40. Additionally, plate 140 further includes recesses149 and grooves 149 a that are identical to recesses 49 and grooves 49 aof plate 40. Clips 155 include protrusions 155 a as discussed above.Plate 140 includes two channels or tracks 136 shaped as dovetail slotsthat extend through plate 140 from trailing side 148 to leading side 150and inferiorly from top side 42. Channels 136 are configured tocorrespond to channels 36 of spacer 12, such that an anchor 80,described below, can fit into both channels 36 and 136 and to aid insecuring prosthesis 10 to an adjacent vertebra. In this manner, plate140 is configured to provide fixation with adjacent vertebrae via bothanchors and screws. The screws secure prosthesis 10 to the inferiorvertebra, and the anchors secure prosthesis 10 to the superior vertebra.Plate 140 also includes a mating feature to mate with instrumentationduring insertion of plate 140 and/or prosthesis 10. In the illustratedembodiment, the mating feature is a plurality of holes 145 extendingfrom trailing side 148 to leading side 150 that can be used with one ormore instruments during insertion of plate 140 and/or prosthesis 10;however, in other examples, the holes 145 may be positioned and sizeddifferently to accommodate the instrumentation or the mating feature canbe any feature that allows for coupling with instrumentation.

Referring to FIGS. 9-11, another embodiment according to the presentinvention is a plate 240 having channels 236 identical to channels 136of plate 140. Plate 240 further includes channels 238 extending throughplate 240 from trailing side 248 to leading side 250 and superiorly frombottom side 244. In this manner, plate 240 is configured to providefixation with the adjacent vertebrae solely via anchors 80, which canfix into superior and inferior vertebrae, respectively. As shown in FIG.11, plate 240 includes a curved profile, in a wave-like manner, alongtrailing side 248. This profile provides stability during attachment ofplate 240 to spacer 12. Additionally, the curved profile adds thicknessto the implant from trailing side 248 to leading side 250, whichcorresponds with the length of the interconnection portion 90 of anchor80, described below. Further, the profile is tapered near lateral sides46, which reduces the overall footprint of the prosthesis.

Plate 240 may alternatively have a flat profile along trailing side 48and may include a connection feature, as described above in connectionwith plates 40, 140, to allow for attachment with retaining mechanism60.

Prosthesis 10 can include a retaining mechanism or plate 60 that isconfigured to be attached to plate 40 and plate 140. As shown in FIGS.12 and 13, retaining mechanism 60 is adapted to prevent the bone screwsand/or anchors from backing out of the holes in plates 40 and 140, whichcould cause instability of prosthesis 10 with respect to the vertebraeand discomfort or injury to the patient. As shown in FIG. 12, retainingmechanism 60 includes a top side 62, bottom side 64 opposite the topside, opposing lateral sides 66, trailing side 68, and leading side 70opposite the trailing side. Retaining mechanism 60 includes a connectionfeature to correspond with the connection feature of plate 40, 140. Inthe illustrated embodiment, the connection feature of retainingmechanism 60 is clips 75 and protrusions 75 a that are similar in natureto clips 55 and protrusions 55 a of plates 40, 140, 240. Clips 75 andprotrusions 75 a create a friction fit with recesses 49, 149 and grooves49 a, 149 a of plates 40, 140 when retaining mechanism 60 is securedthereto, as shown in FIG. 13. However, it is contemplated, as describedabove, that the connection feature may be any feature known in the artto connect the two bodies. Other locations and numbers of the featuresare also contemplated.

Retaining mechanism 60 further includes slots 72 extending therethroughfrom trailing side 68 to leading side 70. Slots 72 are arranged suchthat they run generally parallel to each other and are positionedanteriorly adjacent to screw holes 41 and 43. However, in otherexamples, slots 72 may be positioned in different locations and may havethe same or different orientation on retaining mechanism 60.Additionally, retaining mechanism may have more or less slots 72, whichmay be larger or smaller and in a different shape than that shown inFIG. 12. Slots 72 enable a surgeon to visually confirm that screws areproperly implanted and also provide ventilation of fluids that may bedisposed between retaining mechanism 60 and the corresponding plate 40,140.

FIG. 13 shows prosthesis 10 according to one embodiment of the presentinvention, including spacer 12, plate 40, and retaining mechanism 60,each attached via the appropriate clips and recesses. Prosthesis 10 withplate 40 is to be utilized when only bone screw fixation is desirable.While, prosthesis 10 is shown only with configuration plate 40,alternatively, plate 140 could be attached to spacer 12 and retainingmechanism 60.

FIGS. 14-18D show another embodiment of the present invention as aprosthesis 510 that includes a spacer 512 and a retaining mechanism 561configured to be attached thereto. Spacer 512 includes top and bottomsides 518 and 520, respectively, opposing lateral sides 526, andtrailing and leading sides 522 and 524, respectively. Spacer 512 furtherincludes teeth or serrations 528 on each of top and bottom sides 518 and520, openings 530 for receipt of bone in-growth material, and threeholes 533 for receiving fixation members, such as a bone screw. Eachhole 533 may include a perimeter at a location about a central axis ofthe hole that is fully enclosed within the spacer; alternatively, hole533 may only be partially enclosed within spacer 512. Spacer 512 mayfurther include an opening 546 for engaging with a retaining mechanism561, shown in FIG. 17, and/or for connection with an inserterinstrumentation. Opening 546 is defined by recesses 550, 552 formed inopposing walls 564 and 566 of opening 546. Additionally spacer 512includes slots 554 adapted to receive a mating feature on retainingmechanism 561 (e.g. projections 555).

Spacer 512 further includes channels 536 and 538 on top side 518 andbottom side 520 of the spacer, respectively. Channels 536 and 538 areshaped similarly to those described above in connection with spacer 12.In the present embodiment, there are two channels on top side 518 andtwo channels on bottom side 520 of spacer 512. Channels 536, 538 areformed to accommodate anchors 80, described below. In this manner,spacer 512 may be utilized with bone screws and/or anchors to fix spacer512 to the adjacent vertebrae.

Retaining mechanism 561 is configured to be attached to spacer 512 toprevent the bone screws and/or anchors from backing out of the holesand/or channels, respectively. As shown in FIG. 17, retaining mechanism561 includes a top side 562, a bottom side 564, opposing lateral sides566, a trailing side 568, and a leading side opposite the trailing side.Retaining mechanism 561 is compressible or otherwise deformable toengage with the spacer 512 and/or to assess fusion if the spacercomprises PEEK. As shown in FIG. 17, retaining mechanism 561 has slots571 adapted to allow compression or deformation of retaining mechanism561 upon pressure exerted on lateral sides 566. Slots 571 extend fromtrailing side 568 to leading side 570 and extend from top side 562toward bottom side 564 or vice versa while terminating at a circular end573 in a central portion of retaining mechanism 561. Retaining mechanism561 may include six slots 571; however, in other examples, there aremore or less slots 571 present.

Retaining mechanism 561 includes holes 524 extending from trailing side564 to leading side 568 that are configured to engage an insertioninstrument. This allows such an instrument to exert compression onretaining mechanism to shorten its width when it is installed to spacer512. Retaining mechanism 561 further includes a connection feature toattach to spacer 512. In the present embodiment, retaining mechanism 561includes a projection 555 extending from each lateral side 526.Projections 555 are adapted to attach within slots 554 on spacer 512 toprovide a secure attachment between the spacer and retaining mechanism561 when retaining mechanism 561 is in its relaxed or fully extendedstate. However, other connection features known in the art can be usedto attach retaining mechanism to spacer 512, such as for example othertypes of compression technology. For example, projections 555 can belocated at other areas of retaining mechanism 561 to engage spacer 512.

Although described in connection with spacer 512, features similar oridentical to retaining mechanism 561 may be used in the retainingmechanism attached with spacer 12.

Spacers 12 and 512 may include one or more radiographic markers visiblein FIGS. 1 and 14 at certain locations 29 and 529 on top sides 18 and518, respectively. Spacers 12 and 512 can be comprised of radiolucentpolyetheretherketone (PEEK), polyaryletherketone (PAEK), or the like. Insuch cases, radiographic markers allow for visualization of thepositioning of spacer 12, 512 in imaging taken during and after asurgical procedure. Alternatively, spacer 12, 512 may comprise metal,for example titanium, ceramic, glass, polymer, or any other materialknown for use in the human body. Spacer 12, 512 can be comprised of aporous metal or having a porous metal surface such as a porous titaniumalloy, including Tritanium® by Howmedica Osteonics Corporation. Spacer12, 512 may also comprise one or more surface treatments to encouragebony attachment, such as porous coating, plasma spray coating,hydroxyapatite, or tricalcium phosphate. Retaining mechanisms 60 and 561is preferably comprised of metal, but may be made of PEEK or anothercomposite material.

Certain of the above-described features of spacer 512 and retainingmechanism 561, as well as other aspects of such devices, are furtherdisclosed in U.S. Pat. No. 9,480,577, issued on Nov. 1, 2016, and titled“Retaining Mechanism, Implant, and Tool,” the disclosure of which ishereby incorporated by reference herein.

Different configurations of prosthesis 510 are shown in FIGS. 18A-D.FIG. 18A depicts spacer 512 with three bone screws installed therein,and FIG. 18B shows retaining mechanism 561 in place to prevent screwbackout. Similarly, FIG. 18C depicts spacer 512 with four anchors 80installed therein, and FIG. 18D shows retaining mechanism 561 in placeto aid in securing anchors 80 and preventing their backout. In otherembodiments, any combination of one or more bone screws and one or moreanchors 80 can be utilized with spacer 512, with retaining mechanism 561installed thereafter.

The above-described embodiments are typically sized and shaped for usein the lumbar and thoracic regions of the spinal column. Other sizes,shapes, and geometries of those embodiments are contemplated to adaptthem for use in the cervical spine as well.

FIGS. 19A and B show spacer 612 and plates 640, 640′ that attach to formprosthesis 610 to be used in cervical surgeries. Spacer 612 has similar,but scaled down, features to spacer 12. As shown in FIGS. 19A and B,spacer 612 includes channels or dovetail slots similar to thosedescribed in connection with spacer 12. In the illustrated embodiment,the channels are in the shape of a truncated I-beam, but in otherexamples, the channels may have different shapes, i.e. circular orrectangular, etc. Spacer 612 also includes holes similar to holes 31, 33of spacer 12. In other examples, the holes of spacer 612 may extendthrough the spacer at different angles. Further, spacer 612 includes aconnection feature to attach plates 640, 640′ thereto. In the presentembodiment, the connection feature is similar to recesses 39 of spacer12, however, the recesses of spacer 612 are disposed on the lateralsides. However, spacer 612 may employ any one of, or a combination of, avariety of connection features known in the art. Additionally, spacer612 may include an opening to allow for receipt of bone in-growthmaterial and may further include serrations on various surfaces, i.e.top and bottom surfaces, to allow for fixation with adjacent vertebrae.

Plates 640, 640′ are interchangeable and are both configured to attachto spacer 612. Plate 640 allows for bone screw fixation while plate 640′allows for anchor fixation.

Plate 640 includes a mating hole or hole extension to allow a bone screwto extend through both plate 640 and spacer 612. In the illustratedembodiment, there are two such holes in plate 640; however, there may bemore or less of the holes in other examples. The holes may extendthrough plate 640 at a variety of angles corresponding to alignment withthe holes of spacer 612. Plate 640 includes a connection feature toallow for securement of the plate to spacer 612. In the presentembodiment, plate 640 includes clips similar to clips 55 on plates 40,140, 240, that are configured to snap into the recesses of spacer 612;however, in other examples, the connection feature of retainingmechanism 640 may be any known mechanism that secures the two bodies.Additionally, plate 640 includes a mating feature on an anterior surfaceto allow for engagement with an insertion instrument.

Plate 640′ includes a connection feature and a mating feature, similarto those described in connection with plate 640. In the presentembodiment, plate 640′ includes a plurality of holes similar to holes145, 245 of plates 140, 240, respectively; although, the mating featureof plate 640′ can include any feature known to be used for allowingengagement with such an instrument. Plate 640′ further includes channelsor channel extensions sized and shaped to align with the channels ofspacer 612 and allow for insertion of anchors into prosthesis 610.

Plates 640, 640′ may further include a connection feature to connectplate 640, 640′ with a retaining mechanism having similar features tothose described in connection with retaining mechanisms 60, 561.

FIGS. 20A and B show prosthesis 710 to be used in lateral surgeries.Prosthesis 710 has spacer 712 with either plate 740 or plate 740′attached thereto. Spacer 712 is similar to spacer 12; however, spacer712 has dimensions that are greater in the medial-lateral direction andlesser in the anterior-posterior direction as compared to spacer 12.Spacer 712 includes similar features to spacers 12, 612 including: holesfor receiving bone screws, channels for receiving anchors, and aconnection feature for securement with plates 740, 740′. Additionally,spacer 712 may include serrations and an opening for receipt of boneingrowth material.

Prosthesis 710 further includes one of plate 740 and 740′, which areinterchangeable. Plates 740 and 740′ both include a connection featureand a mating feature, as described in connection with plates 640, 640′.Plate 740 includes bone screw holes or extensions similar to thosedescribed in connection with plates 40, 140, 640. The holes areconfigured to be aligned with the holes of spacer 712 and to receivebone screws for fixation of prosthesis 710 to bone. Plate 740′ includeschannels similar to the channels described in connection with plates140, 240, 640′ configured to align with the channels of spacer 712, suchthat anchors can be inserted into prosthesis 710 and provide fixation ofthe prosthesis to bone.

Additional plates similar to plates 640, 640′, 740, 740′ can be utilizedto include one or more holes and one or more channels. Specifically, aplate can include one hole and one channel. The features described abovecan be used in connection with prostheses 610, 710 to be used duringcervical and lateral surgeries, respectively. Prostheses 610, 710include spacers 612, 712 having similar features to spacer 12 and plates640, 640′, 740, 740′ having similar features to plates 40, 140, 240.Further prostheses 610, 710 may include a retaining mechanism havingsimilar features to those described in connection with retainingmechanisms 60, 561. Plates 640, 640′, 740, 740′ may include a connectionfeature, similar to those described in connection with plates 40, 140,to attach the retaining mechanism to the plate.

FIGS. 21-23, show anchor 80 used as a fixation method with prosthesis 10and 510. Anchor 80 may be generally elongate with a leading end 86 and atrailing end 88. The anchor 80 may include an interconnection portion 90extending between leading end and trailing ends 86, 88. Interconnectionportion 90 is shaped and sized to matingly attach with the channels 36,38 of spacer 12, channels 136 of plate 140, channels 236, 238 of plate240, and channels 536 and 538 of spacer 512. In the present embodiment,the interconnection portion is a dovetail beam 90 that can slideablyattach to the plates and spacers. Anchor 80 includes a stop feature,flange 81, to prevent the anchor from migrating too far posteriorly intoprosthesis 10 after implantation. In the illustrated embodiment, thestop feature is flange 81 near trailing end 88. Anchor 80 furtherincludes a locking feature to prevent the anchor from migratinganteriorly after implantation. In the present embodiment, the lockingfeature is flexible tab 82 disposed near the trailing end 88 of thedovetail beam 90. Flange 81 and flexible tab 82 can cooperate withplates 40, 140, 240 to maintain anchor 80 in its implanted position inthe spacer 12.

Anchor 80 includes a fixation portion 89 that secures anchor 80 to theadjacent vertebra. Fixation portion 89 resists axial tensile andcompressive forces that may be the result of spinal flexion andextension or right and left lateral bending. In the present embodiment,the fixation portion is a plate 89 extending between the leading andtrailing ends 86, 88 and spaced apart from the dovetail beam 90 by leg96, 98 extending generally perpendicularly between the dovetail beam 90and fixation plate 89. First leg 96 is positioned near leading end 86,while second leg 98 is positioned near trailing end 88. This positioningof legs 96, 98 allows for an opening between legs 96, 98 so that bonemass may be radiographically viewed. In the present embodiment, plate 89includes a top surface 91 and a bottom surface 92. Plate 89 tapers to apoint at leading end 86, which reduces the magnitude of the forcerequired for insertion of anchor 80 into the bone.

Fixation plate 89 may be sharpened around a portion of its profile tocreate a cutting edge 93, provided to cut through bone. Cutting edge 93may extend only on leading end 86 or may extend to the lateral sides ofplate 89. In the present embodiment, cutting edge 93 is curved adjacentbottom surface 92 and flat adjacent top surface 91. Cutting edge 93 mayadditionally be asymmetrically positioned nearer to top surface 91. Thecurved-flat shape of cutting edge 93 as well as the asymmetricpositioning may bias plate 89 and cause it to take a path that may atleast slightly diverge from a path taken by dovetail beam 90 as anchor80 engages prosthesis 10 and one of the adjacent vertebrae. In thismanner, anchor 80 lifts away from dovetail beam 90 when inserted. Whentwo or more anchors 80 are placed on superior and inferior sides ofprosthesis 10, the adjacent vertebrae are compressed against prosthesis10 as anchors 80 advance into the bone.

A portion of fixation plate 89 may not be sharpened, specifically aportion near trailing end 88 to prevent the anchor from migrating afterimplantation. Additionally, cutting edge 93 may include teeth orserrations 97 to further limit migration. Further, plate 89 includes awindow 99 extending from top and bottom surfaces of plate 89.

Anchor 80 may be made of metal, ceramic, glass, polymer, or any otherstructural material known for use in the human body. Anchor 80 may alsocomprise one or more surface treatments to encourage bony attachment,such as porous coating, plasma spray coating, hydroxyapatite, ortricalcium phosphate. In another example, anchor 80 may compriseautograft bone, allograft bone, or bone graft substitute.

The anchors and other aspects thereof are further disclosed in U.S. Pat.No. 8,349,015, issued on Jan. 8, 2013, and titled “IntervertebralImplant With Integrated Fixation,” the disclosure of which is herebyincorporated by reference herein.

A method of implanting intervertebral prosthesis 10 in the lumbar spinefrom an anterior surgical approach will now be described. It isunderstood that the same or similar methods may be employed to implantthe prosthesis 10 at any level of the spine, and from any surgicalapproach, including lateral, without departing from the scope of thepresent invention. More specifically, it is contemplated that prosthesis10 may be implanted from an anterior, posterior, posterior-lateral,lateral, or other surgical approach.

At least a portion of an intervertebral disc between adjacent vertebraeis removed using tools and techniques known in the art. A surgeonevaluates the bone integrity of the adjacent vertebrae and selects oneof plates 40, 140, 240 to be attached to spacer 12. In selecting theplate, the surgeon considers whether screws, anchors, or both aredesirable or required for fixation in light of the pathology, patient'sanatomy, and/or the surgeon's preference. The selected plate 40, 140,240 is attached to spacer 12. The spacer-plate configuration is theninserted into the prepared disc space. If the surgeon selects plate 40or 140, then a screw is inserted into the hole and hole extension of theplates 40, 140 and into communication with the adjacent vertebrae. Ifthe surgeon selects plate 140 or 240, an anchor, such as anchor 80, isinserted into the channel and the channel extension of plates 140, 240and into communication with the adjacent vertebrae. Of course any numberof screws and/or anchors can be used as desirable according to theselected plate. One or more holes and channels can be left empty aswell. After the step of inserting the screws and/or anchor into plates40 or 140, the method can further include the step of attachingretaining mechanism 60 to plate 40 or 140 to prevent screw backout. Atab on anchor 80 interacts with plates 140, 240 to prevent backout.

A method of implanting prosthesis 510 in the lumbar spine from ananterior surgical approach includes inserting spacer 512 into theprepared disc space and inserting a screw and/or anchor, such as anchor80, into holes 533 and channels 536, 538 and into communication with theadjacent vertebrae. The method further includes attaching retainingmechanism 61 to the spacer 12 by compressing retaining mechanism 61 toprevent backout of the screws and/or anchors.

A method of implanting prosthesis 610 in the cervical spine from ananterior surgical approach includes similar steps to the method ofimplanting prosthesis 10 in the lumbar spine, as described above. Thesurgeon evaluates the bone integrity of the adjacent vertebrae, selectsthe appropriate fixation, screws or anchors, and selects one of plates640, 640′ to be attached to spacer 612. The spacer-plate configurationis then inserted into the prepared disc space. The method of fixation,screws or anchors, are then inserted into the hole, hole extension orchannel, channel extension and into communication with the vertebrae. Ofcourse any number of screws and/or anchors can be used as desirableaccording to the selected plate. One or more holes and channels can beleft empty as well.

The methods described in connection with prostheses 10, 610 may be usedto implant prosthesis 710 in the lumbar spine but from a lateralsurgical approach. Prostheses as described herein can be inserted via ananterior approach, a lateral approach, or a posterior-lateral approachas applicable.

Various surgical instruments can be utilized to insert, position, andeven remove the above-described prosthetic devices. For example, certaininstruments are further disclosed in U.S. patent application Ser. No.13/389,298, filed on Jul. 16, 2012, and titled “Intervertebral ImplantWith Integrated Fixation,” U.S. Pat. No. 9,033,993, issued on May 19,2015, and titled “Intervertebral Implant With Integrated Fixation,” andin U.S. Pat. No. 9,480,577, issued on Nov. 1, 2016, and titled“Retaining Mechanism, Implant, and Tool,” the disclosures of which arehereby incorporated by reference herein.

Although aspects of the invention(s) herein have been described withreference to particular embodiments, it is to be understood that theseembodiments are merely illustrative of certain features of the presentinvention(s). It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention(s) as defined by the appended claims.

It will also be appreciated that the various dependent claims and thefeatures set forth therein can be combined in different ways thanpresented in the initial claims. It will also be appreciated that thefeatures described in connection with individual embodiments may beshared with others of the described embodiments.

The invention claimed is:
 1. A kit for intervertebral disc repaircomprising: a spacer including a hole for receiving a screw and achannel for receiving an anchor; a first plate configured to attach tothe spacer, the first plate having a hole extension that aligns with thehole when the first plate is attached to the spacer; and a second plateconfigured to attach to the spacer, the second plate having a channelextension that aligns with the channel when the second plate is attachedto the spacer, wherein the first and second plates are detached from oneanother so that in an assembled condition, when one of the first plateand the second plate is attached to the spacer, the other of the firstplate and the second plate is detached from both the spacer and thefirst plate; wherein the hole has a different shape from the channel. 2.The kit of claim 1, wherein a perimeter of the hole at a location abouta central axis of the hole is fully enclosed within the spacer.
 3. Thekit of claim 2, wherein the central axis of the hole extends through asuperior surface and a front surface of the spacer.
 4. The kit of claim3, further comprising a second hole having a perimeter at a locationabout a central axis of the second hole that is fully enclosed withinthe spacer.
 5. The kit of claim 4, wherein the central axis of thesecond hole extends through an inferior surface and the front surface ofthe spacer.
 6. The kit of claim 1, wherein the channel is a dovetailslot and extends along a superior surface or an inferior surface of thespacer.
 7. The kit of claim 6, wherein the channel is open toward thesuperior or inferior surface along which it extends.
 8. The kit of claim6, wherein the channel extends between and intersects both a leadingside and a trailing side of the spacer.
 9. The kit of claim 8, whereinthe channel extends along a central axis that forms a non-perpendicularangle with the leading side of the spacer.
 10. The kit of claim 1,wherein a perimeter of the channel about a central axis of the channelis not fully enclosed within the spacer at any location about thecentral axis of the channel.
 11. The kit of claim 1, further comprisinga third plate configured to attach to the spacer, the third plate havinga hole extension that aligns with the hole when the third plate isattached to the spacer and a channel extension that aligns with thechannel when the third plate is attached to the spacer.
 12. The kit ofclaim 1, further comprising an anchor configured to extend into thechannel and the channel extension and into one of the adjacent vertebraewhen the second plate is attached to the spacer.
 13. The kit of claim 1,further comprising a screw configured to extend through the hole and thehole extension and into one of the adjacent vertebrae when the firstplate is attached to the spacer.
 14. The kit of claim 1, furthercomprising a securing plate configured to attach to the first plate,wherein the securing plate includes a slot therein, and wherein the slotis configured to align with the hole extension of the first plate whenthe securing plate is attached to the first plate.
 15. The kit of claim1 further comprising: a securing plate configured to engage either oneor both of the first plate and the second plate.
 16. A kit forintervertebral disc repair comprising: a spacer having a first surface,the first surface including a hole for receiving a screw and a channelfor receiving an anchor extending through the first surface; a firstplate configured to attach to the first surface of the spacer, the firstplate having a hole extension that aligns with the hole when the firstplate is attached to the spacer; and a second plate configured to attachto the first surface of the spacer, the second plate having a channelextension that aligns with the channel when the second plate is attachedto the spacer, wherein the channel extension has a different shape fromthe hole extension.
 17. A kit for intervertebral disc repair comprising:a spacer including a hole for receiving a screw and a channel forreceiving an anchor, wherein a perimeter of the hole at a location abouta central axis of the hole is fully enclosed within the spacer; a firstplate configured to attach to the spacer, the first plate having a holeextension that aligns with the hole when the first plate is attached tothe spacer; and a second plate configured to attach to the spacer, thesecond plate having a channel extension that aligns with the channelwhen the second plate is attached to the spacer, wherein the first plateand the second plate interchangeably attach to the spacer.